The present invention relates to an apparatus and method for exposing an edge of a substrate to manufacture a flat display device, and more particularly, to an apparatus and method for exposing an edge of a substrate, in which an exposure time period for exposing the edge of the substrate is reduced.
Generally, a photolithography process is used to pattern a substrate in a process of manufacturing a semiconductor device or a flat display device.
The photolithography process includes a deposition process of depositing a photoresist on a substrate, an exposure process of exposing the photoresist deposited on the substrate, and a development process of developing the exposed substrate.
The exposure process is to selectively expose the photoresist deposited on the substrate using a mask.
Meanwhile, a process defect occurs due to foreign materials generated by peeling at the edge of the substrate during movement, exposure or development of the substrate. To prevent such peeling at the edge of the substrate, an edge exposure process is performed before the exposure process to remove the edge of the substrate at a certain width.
FIG. 1 is a block diagram illustrating a related art apparatus for exposing an edge of a substrate.
Referring to FIG. 1, the related art apparatus for exposing an edge of a substrate includes a loading/unloading unit 10 loading and unloading the substrate, and an edge exposure unit 20 exposing the edge of the substrate loaded by the loading/unloading unit 10.
The loading/unloading unit 10 loads the substrate externally deposited with a photoresist into the edge exposure unit 20 using a robot arm. Also, the loading/unloading unit 10 unloads the substrate exposed by the edge exposure unit 20 from the edge exposure unit 20 using the robot arm.
The edge exposure unit 20 exposes the edge, i.e., long and short sides, of the substrate loaded by the loading/unloading unit 10 at a certain width.
FIG. 2 illustrates the related art edge exposure unit 20 shown in FIG. 1.
Referring to FIG. 2 in connection with FIG. 1, the related art edge exposure unit 20 includes a stage 21 supporting the substrate deposited with the photoresist, a driving shaft 22 moving the stage 21 in a first direction (X axis) and rotating the stage 21, a rail 23 guiding the driving shaft 22 to move the driving shaft 22 to the first direction, and an exposure unit provided in the rail 23 to expose the edge of the substrate.
The stage 21 includes a plurality of lift pins 25 supporting and fixing the substrate loaded from the loading/unloading unit 10. The lift pins 25 are ascended and descended by a driving device (not shown) to adsorb the substrate under the vacuum state.
The driving shaft 22 is linked to the driving device to move the stage 21 in the first direction (X axis) along the rail 23. Also, the driving shaft 22 is rotated by the driving device to rotate the stage 21.
The rail 23 guides the driving shaft 22 to move the driving shaft 22 to the first direction (X axis).
The exposure unit includes a support bar 24 arranged to vertically cross the rail 23, first and second optical systems 26a and 26b arranged in parallel at a side of the support bar 24, and a distance controller 28 controlling the distance between the first and second optical systems 26a and 26b. 
The support bar 24 is fixed to the rail 23 to vertically cross the rail 23.
Each of the first and second optical systems 26a and 26b are spaced apart from each other to correspond to the distance between the long sides or the short sides of the substrate. Each of the first and second optical systems 26a and 26b irradiates light toward the long sides or the short sides of the substrate to expose the edge of the substrate.
The distance controller 28 controls the distance between the first and second optical systems 26a and 26b to correspond to the distance between the long sides or the short sides of the substrate.
FIGS. 3A to 3G are sectional views illustrating exposure process steps of exposing the edge of the substrate using the related art edge exposure unit 20.
The exposure process steps of exposing the edge of the substrate according to the related art will be described as follows.
First, as shown in FIG. 3A, the substrate 2 deposited with the photoresist is loaded, as shown by arrow 30, onto the stage 21 of the home position by the robot arm of the loading/unloading unit 10. If the robot arm of the loading/unloading unit 10 on which the substrate is mounted is positioned on the stage 21, the lift pins 25 are ascended by the driving device to lift the substrate 2 mounted on the robot arm. If the substrate 2 is lifted at a certain height by the lift pins 25, the robot arm returns to the loading/unloading unit 10. At this time, the distance between the first and second optical systems 26a and 26b is set by the distance controller 28 to correspond to the distance between the long sides of the substrate 2.
When the robot arm is taken out from the stage 21, the lift pins 25 descend and are fixed to the surface of the stage 21 as shown in FIG. 3B.
Subsequently, as shown in FIG. 3C, the driving shaft 22 moves to the first direction (X axis) along the rail 23 so that the stage 21 moves, as shown by arrow 31, to the exposure unit. When the substrate 2 moves near the exposure unit, the first and second optical systems 26a and 26b irradiate light toward both edges 29a of the long sides of the substrate 2 to expose the long sides of the substrate 2. At this time, the first and second optical systems 26a and 26b may be driven by a sensing signal of a sensor (not shown) that senses the position of the substrate 2.
Subsequently, as shown in FIG. 3D, when the long sides of the substrate 2 are completely exposed, the driving shaft 22 is clockwise rotated, as shown by arrow 32, at an angle of 90° as shown in FIG. 3D. At this time, the distance between the first and second optical systems 26a and 26b is set, as shown by arrow 33, by the distance controller 28 to correspond to the distance between the short sides of the substrate 2.
Next, as shown in FIG. 3E, when the substrate 2 is completely rotated, the driving shaft 22 moves to the first direction (X axis) along the rail 23 so that the stage 21 moves to the home position. If the substrate 2, which is moving to the home position, moves near the exposure unit, the first and second optical systems 26a and 26b irradiate light toward both edges 29b of the short sides of the substrate 2 to expose the short sides of the substrate 2.
Subsequently, as shown in FIG. 3F, when the short sides of the substrate 2 are completely exposed, the driving shaft 22 is clockwise rotated, as shown by arrow 34, at an angle of 900 as shown in FIG. 3G. At this time, the distance between the first and second optical systems 26a and 26b is set by the distance controller 28 to correspond to the distance between the long sides of the substrate 2.
Then, when rotation of the substrate 2 is completed, the substrate 2 whose long and short sides have completely been exposed is ascended at a certain height by the lift pins 25. The robot arm of the loading/unloading unit 10 is inserted between the ascended substrate 2 and the stage 21. Subsequently, the lift pins 25 are descended into the stage 21 so that the substrate 2 is mounted on the robot arm and thus unloaded from the loading/unloading unit 10.
Consequently, in the related art apparatus and method for exposing the edge of the substrate, as shown in FIGS. 3A to 3G, the edge of the substrate 2 is exposed in the order of loading of the substrate 2, movement of the stage 21 and exposure of the long sides, rotation of the stage 21, movement of the stage 21 and exposure of the short sides, rotation of the stage 21, and unloading of the substrate 2.
However, the related art apparatus and method for exposing the edge of the substrate have several problems.
Since both a reciprocating movement time period of the stage 21 to the first direction (X axis) and a rotational time period of the stage 21 are required, the process time of exposing the edge of the substrate 2 increases.
Further, since the substrate 2 is unloaded through a port after being loaded into the port, the process time of exposing the edge of the substrate 2 increases due to a standby time period of the substrate 2.
Moreover, since the stage 21 should be rotated, the size of the apparatus increases.